Selective jejunal manipulation causes postoperative pan-enteric inflammation and dysmotility

Risk factors for post-operative ileus in patients with anterior resection for rectal cancer. A single center cohort

BACKGROUND

Postoperative ileus (POI) is a major cause of morbidity in patients undergoing colorectal surgery. The aim of our study was to evaluate potential risk factors for POI in cases with anterior resection for rectal cancer.

METHODS

A retrospective cohort study was performed on 136 patients who underwent open anterior resection for rectal cancer between 2004 and 2018 at a single tertiary referral center. POI was defined as reinsertion of nasogastric tube or nil per os by postoperative day 4 and/or administration of neostigmine postoperatively. Uni- and multivariate analysis was performed to identify potential risk factors for POI.

RESULTS

POI was observed in 18 patients (13.2%). Epidural anesthesia, type of ostomy, and history of abdominal surgery were not found to be related with POI. Advanced age was a statistically significant risk factor both in the uni- and in the multivariate analyses. An increase in age by 1 year was found to increase the odds of POI by 5% [95%CI: 0.4%-9.7%; p = 0.032].

CONCLUSION

Increased age was identified as a non-modifiable, patient-related risk factor for POI after anterior resection for rectal cancer. This finding is of particular importance as it turns the focus on the elderly patient and underlines the need for close clinical observation of this subgroup and liberal use of preventive and/or therapeutic measures postoperatively.

Impact of warm saline irrigation, hyperthermic intraperitoneal chemotherapy on postoperative pain in primary ovarian cancer from the KOV-HIPEC-01 randomized trial

BACKGROUND

Hyperthermic intraperitoneal chemotherapy (HIPEC) has emerged as a treatment option at the time of cytoreductive surgery after neoadjuvant chemotherapy. The effect of active warming of HIPEC on postoperative pain needs to be investigated. This study aimed to investigate whether HIPEC reduces postoperative pain.

METHODS

From the KOV-HIPEC-01 trial, a randomized controlled trial of HIPEC for advanced primary ovarian cancer, 184 patients with a residual tumor size <1 cm were randomly assigned to the HIPEC and control groups at a 1:1 ratio. The consumption of analgesics and pain scales were analyzed. Hyperthermic intraperitoneal chemotherapy was administered after cytoreductive surgery. The primary objective was to compare the consumption of opioids measured in morphine milligram equivalents and non-opioids measured as the maximum daily dose between the HIPEC and control groups. The secondary objective was to compare the minimum and maximum pain intensities on numeric rating scales between the two groups using a linear mixed model.

RESULTS

Lesser consumption of non-opioids, with a lower mean maximum daily dose on postoperative days 1 and 2, was observed. The HIPEC group also experienced lower maximum pain intensities on postoperative day 1. No overall differences in the minimum or maximum pain intensities were observed on postoperative day 7.

CONCLUSION

The addition of HIPEC to cytoreductive surgery did not lead to increased postoperative pain, as demonstrated by a reduction in the use of analgesics and lower scores on postoperative pain scales during the early postoperative period.

The efficacy and results of medical treatment in postoperative ileus

Background

Postoperative paralytic ileus refers to the disruption of the normal coordinated propulsive motor activity of the gastrointestinal system following surgery. Surgery causes inflammation in the muscle walls of organs with an intestinal lumen that, in turn, leads to a decrease in intestinal motility.

Aim

The aim of this study was to investigate the efficacy of gastrografin, neostigmine, and their combined administration in patients diagnosed with paralytic ileus in the postoperative period.

Patients and Methods

One-hundred twelve patients were included from January 2017 and November 2019. The retrospective study is involving prolonged postoperative ileus cases following colorectal surgery. The effect of gastrografin, neostigmine, and gastrografin neostigmine combination was compared retrospectively in the treatment of prolonged ileus after surgery.

Results

The study covered 112 patients. Gastrografin was administered to 63 patients; neostigmine was administered to 29, while 20 patients received the combination of the two. Data pertaining to the comparison of the two groups revealed that patients in the gastrografin group were discharged earlier than those in the neostigmine group. Further, patients in the combined group had earlier gas and/or stool discharge and were also discharged from the hospital earlier than those in the neostigmine group.

Conclusion

Gastrografin and combined use of gastrografin and neostigmine are effective and viable methods for postoperative ileus cases. Gastrografin can safely be used in patients with anastomoses.

Lateral decubitus single position anterior posterior surgery improves operative efficiency, improves perioperative outcomes, and maintains radiological outcomes comparable with traditional anterior posterior fusion at minimum 2-year follow-up

BACKGROUND CONTEXT

The advantages of Lateral Single Position surgery (LSPS) in the perioperative period has previously been demonstrated, however 2-year postoperative outcomes of this novel technique have not yet been compared to circumferential anterior-posterior fusion (FLIP) at 2-years postoperatively.

PURPOSE

Evaluate the safety and efficacy of LSPS versus gold-standard FLIP STUDY DESIGN/SETTING: Multi-center retrospective cohort review.

PATIENT SAMPLE

Four hundred forty- two patients undergoing lumbar fusion via LSPS or FLIP OUTCOME MEASURES: Levels fused, operative time, estimated blood loss, perioperative complications, and reasons for reoperation at 30-days, 90-days, 1-year, and 2-years. Radiographic outcomes included lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), PI-LL mismatch, and segmental lumbar lordosis.

METHODS

Patients were grouped as LSPS if anterior and posterior portions of the procedure were performed in the lateral decubitus position, and FLIP if patients were repositioned from supine or lateral to prone position for the posterior portion of the procedure under the same anesthetic. Groups were compared in terms of demographics, intraoperative, perioperative and radiological outcomes, complications and reoperations up to 2-years follow-up. Measures were compared using independent samples or paired t-tests and chi-squared analyses with significance set at p<.05.

RESULTS

Four hundred forty- two pts met inclusion, including 352 LSPS and 90 FLIP pts. Significant differences were noted in age (62.4 vs 56.9; p≤.001) and smoking status (7% vs 16%; p=.023) between the LSPS and FLIP groups. LSPS demonstrated significantly lower Op time (97.7min vs 297.0 min; p<.001), fluoro dose (36.5mGy vs 78.8mGy; p<.001), EBL (88.8mL vs 270.0mL; p<.001), and LOS (1.91 days vs 3.61 days; p<.001) compared to FLIP. LSPS also demonstrated significantly fewer post-op complications than FLIP (21.9%vs 34.4%; p=.013), specifically regarding rates of ileus (0.0% vs 5.6%; p<.001). No differences in reoperation were noted at 30-day (1.7%LSPS vs 4.4%FLIP, p=.125), 90-day (5.1%LSPS vs 5.6%FLIP, p=.795) or 2-year follow-up (9.7%LSPS vs 12.2% FLIP; p=.441). LSPS group had a significantly lower preoperative PI-LL (4.1° LSPS vs 8.6°FLIP, p=.018), and a significantly greater postoperative LL (56.6° vs 51.8°, p = .006). No significant differences were noted in rates of fusion (94.3% LSPS vs 97.8% FLIP; p=.266) or subsidence (6.9% LSPS vs 12.2% FLIP; p=.260).

CONCLUSIONS

LSPS and circumferential fusions have similar outcomes at 2-years post-operatively, while reducing perioperative complications, improving perioperative efficiency and safety.

Mechanosensing in the Physiology and Pathology of the Gastrointestinal Tract

Normal gastrointestinal function relies on sensing and transducing mechanical signals into changes in intracellular signaling pathways. Both specialized mechanosensing cells, such as certain enterochromaffin cells and enteric neurons, and non-specialized cells, such as smooth muscle cells, interstitial cells of Cajal, and resident macrophages, participate in physiological and pathological responses to mechanical signals in the gastrointestinal tract. We review the role of mechanosensors in the different cell types of the gastrointestinal tract. Then, we provide several examples of the role of mechanotransduction in normal physiology. These examples highlight the fact that, although these responses to mechanical signals have been known for decades, the mechanosensors involved in these responses to mechanical signals are largely unknown. Finally, we discuss several diseases involving the overstimulation or dysregulation of mechanotransductive pathways. Understanding these pathways and identifying the mechanosensors involved in these diseases may facilitate the identification of new drug targets to effectively treat these diseases.

Small Intestine Bacterial Overgrowth Can Form an Indigenous Proinflammatory Environment in the Duodenum: A Prospective Study

Small intestinal bacterial overgrowth (SIBO) contributes to the formation of an inflammatory environment in various intestinal and extraintestinal diseases. Cytokines that participate in these mechanisms are yet to be examined. Upper gastrointestinal endoscopy with duodenal aspiration was performed in 224 patients. Quantitative cultures of aerobic species were performed, concentrations of interleukin 1β (IL-1β), interleukin 6 (IL-6), and tumor necrosis factor alpha (TNF-α) were measured, and loads of Escherichia coli, Klebsiella pneumoniae, Methanobevibacter smithii, and Aeromonas spp. were detected via real-time PCR in the duodenal fluid. Analysis showed that the odds ratio (OR) for elevated IL-1β levels was 2.61 (1.06–6.43, p = 0.037) among patients with SIBO compared to patients without SIBO, while there was no significant difference at elevated IL-6 and TNF-α levels between patients with and without SIBO, using ≥10³ cfu/mL as a cut-off. The presence of all three elevated cytokine levels has OR 3.47 (1.06–11.34, p = 0.030) among patients with SIBO. Klebsiella pneumoniae detection was positively related with IL-6 and TNF-α levels, when Methanobevibacter smithii was positively related with IL-1β levels. The presence of SIBO is associated with elevated IL-1β levels in the duodenal fluid. There is a high prevalence of all three proinflammatory cytokine levels elevated (IL-1β, IL-6, and TNF-α) in the duodenal fluid among patients with SIBO.

Post-cesarean ileus: An assessment of incidence, risk factors and outcomes

OBJECTIVE

To estimate the frequency of post cesarean paralytic ileus and to identify associated risk factors and outcomes.

STUDY DESIGN

A retrospective cohort study of woman who underwent cesarean delivery between 2005 and 2019. All parturients who had cesarean delivery were stratified and compared according to whether or not they were diagnosed with a paralytic ileus. Women were excluded if they had an intestinal injury or repair during the cesarean or if they suffered from a post cesarean mechanical bowel obstruction diagnosed during re-laparotomy. Basic demographics, obstetric history, current delivery characteristics, re-suturing indications and outcomes were obtained and analyzed. Univariate analyses were followed by a multivariate analysis (adjusted Odds Ratio (aORs) ; [95% Confidence Interval]).

RESULTS

A total of 23,486 women met the inclusion and exclusion criteria of which 135 (0.6%) were diagnosed with paralytic ileus whilst 23,347 (99.4%) did not and served as the control group. Multivariate analysis revealed that an estimated intra-operative blood loss ≥ 1000 ml was the most significant risk factor for post cesarean paralytic ileus (aOR 2.27 (1.18-4.36)), followed by multifetal gestation (aOR 2.08 (1.24-3.51)), corporeal uterine incision (aOR 1.97 (1.07-3.63)), use of topical hemostatic agents (aOR 1.78 (1.19-2.66)) and increasing maternal age (aOR 1.78 (1.19-2.66)). Regarding maternal outcomes, post cesarean paralytic ileus was associated with higher rates of postpartum hemorrhage (44.4% vs. 13.4%, p < 0.01), transfusion of blood products (23.7% vs. 3.9%, p < 0.01), post-cesarean exploratory laparotomy (4.4% vs. 0.1%, p < 0.01) and prolonged hospital stay (32.6% vs. 5.2%, p < 0.01).

CONCLUSION

In our population, whilst post cesarean paralytic ileus is infrequent, when it occurs it is associated with increased short-term maternal morbidity.

Post-operative ileus: definitions, mechanisms and controversies

Post-operative ileus (POI) is a syndrome of impaired gastrointestinal transit which occurs following abdominal surgery. There are few effective targeted therapies for ileus, and research has been limited by inconsistent definitions and an incomplete understanding of the underlying pathophysiology. Despite considerable effort, there remains no widely-adopted definition of ileus, and recent work has identified variation in outcome reporting is a major source of heterogeneity in clinical trials. Outcomes should be clearly-defined, clinically-relevant, and reflective of the underlying biology, impacts on hospital resources and quality of life. Further collaborative efforts will be needed to develop consensus definitions and a core outcome set for postoperative gastrointestinal recovery. Investigation into the pathophysiology of POI has been hindered by use of low-resolution techniques and difficulties linking cellular mechanisms to dysmotility patterns and clinical symptoms. Recent evidence has suggested the common assumption of post-operative GI paralysis is incorrect, and that the distal colon becomes hyperactive following surgery. The post-operative inflammatory response is important in the pathophysiology of ileus, but the time course of this in humans remains unclear, with the majority of evidence coming from animal models. Future work should investigate dysmotility patterns underlying ileus, and identify biomarkers which may be used to diagnose, monitor and stratify patients with ileus.

Single position circumferential fusion improves operative efficiency, reduces complications and length of stay compared with traditional circumferential fusion

BACKGROUND CONTEXT

Anterior lumbar interbody fusion (ALIF) and lateral lumbar interbody fusion (LLIF) with percutaneous posterior screw fixation are two techniques used to address degenerative lumbar pathologies. Traditionally, these anterior-posterior (AP) surgeries involve repositioning the patient from the supine or lateral decubitus position to prone for posterior fixation. To reduce operative time (OpTime) and subsequent complications of prolonged anesthesia, single-position lumbar surgery (SPLS) is a novel, minimally invasive alternative performed entirely from the lateral decubitus position.

PURPOSE

Assess the perioperative safety and efficacy of single position AP lumbar fusion surgery (SPLS).

STUDY DESIGN

Multicenter retrospective cohort study.

PATIENT SAMPLE

Three hundred and ninety patients undergoing AP surgery were included, of which 237 underwent SPLS and 153 were in the Flip group.

OUTCOME MEASURES

Outcome measures included levels fused, percentage of cases including L5-S1 fusion, fluoroscopy radiation dosage, OpTime, estimated blood loss (EBL), length of stay (LOS), and perioperative complications. Radiographic analysis included lumbar lordosis (LL), pelvic incidence, pelvic tilt, and segmental LL.

METHODS

Patients undergoing primary ALIF and/or LLIF surgery with bilateral percutaneous pedicle screw fixation between L2-S1 were included over a 4-year period. Patients were classified as either traditional repositioned "Flip" surgery or SPLS. Outcome measures included levels fused, percentage of cases including L5-S1 fusion, fluoroscopy radiation dosage, OpTime, EBL, LOS, perioperative complications. Radiographic analysis included LL, pelvic incidence, pelvic tilt, and segmental LL. All measures were compared using independent samples t-tests and chi-squared analyses as appropriate with significance set at p < .05. Propensity matching was completed where demographic differences were found.

RESULTS

Three hundred and ninety patients undergoing AP surgery were included, of which 237 underwent SPLS and 153 were in the Flip group. Age, gender, BMI, and CCI were similar between groups. Levels fused (1.47 SPLS vs 1.52 Flip, p = .468) and percent cases including L5-S1 (31% SPLS, 35% Flip, p = .405) were similar between cohorts. SPLS significantly reduced OpTime (103 min vs 306 min, p < .001), EBL (97 vs 313 mL, p < .001), LOS (1.71 vs 4.12 days, p < .001), and fluoroscopy radiation dosage (32 vs 88 mGy, p < .001) compared to Flip. Perioperative complications were similar between cohorts with the exception of postoperative ileus, which was significantly lower in the SPLS group (0% vs 5%, p < .001). There was no significant difference in wound, vascular injury, neurological complications, or Venous Thrombotic Event. There was no significant difference found in 90-day return to operating room (OR).

CONCLUSIONS

SPLS improves operative efficiency in addition to reducing blood loss, LOS and ileus in this large cohort study, while maintaining safety.

Erythropoietin promotes functional recovery in a mouse model of postoperative ileus

BACKGROUND

Dysmotility and postoperative ileus (POI) are major clinical problems after surgical trauma and it is associated with increased intestinal inflammation and oxidative stress. Despite the high occurrence of POI following intra-abdominal surgeries, no effective treatment is currently available. Erythropoietin (EPO) is a multifunctional tissue-protective cytokine with potent anti-inflammatory and anti-oxidative properties, and it is an FDA approved medicine for clinical use. While both EPO and EPO receptors (EPOR) are widely expressed in the gut, the role of EPO in POI is largely unknown. This study was designed to explore the possible beneficial effect of EPO in a mouse model of POI.

METHODS

Mice were subjected to intestinal manipulation to induce standard POI and intestinal transit time was determined at 24-h post-injury with or without EPO treatment (5000 units/kg, once, IP, immediately after intestinal trauma). Intestinal samples were harvested for histological and immunohistochemical analysis.

RESULTS

Systemic EPO significantly improved intestinal transit time compared with control group and it was associated with significantly increased levels of tissue macrophages and reduced levels of oxidative stress.

CONCLUSIONS AND INFERENCES

This is the first pre-clinical study to document novel beneficial effects of EPO in gut dysmotility and our findings suggest that the beneficial effects of EPO in POI is predominantly mediated by its anti-oxidative and immunomodulatory properties.

The role of tibial nerve stimulation for enhanced postoperative recovery after colorectal surgery: a double-blind, parallel-group, randomized controlled trial

BACKGROUND

Postoperative ileus (POI) is the most common cause of prolonged hospital stay following abdominal surgery, despite an optimized enhanced recovery after surgery (ERAS) program. The aim of the study was to evaluate the role of postoperative transcutaneous electrical tibial nerve stimulation (TTNS) in the recovery of bowel function and in shortening hospital stay after colonic resection.

METHODS

Patients having elective laparoscopic colonic surgery within an ERAS program at our institution between June 2016 and June 2019 were enrolled and randomly assigned to a treatment protocol with TTNS or sham electrical stimulation. The primary endpoint was the time of recovery of gastrointestinal motility, measured as the first passage of stool. Secondary endpoints included: first passage of flatus, length of hospital stay, and complication rate related to the use of TTNS.

RESULTS

One hundred and seventy patients who had right hemicolectomy (median age 71 years (range 43-89 years); 47.5% women) and 170 patients who had left colectomy (median age 67 years range (37-92 years); 41.5% women) were enrolled. The only factor significantly affected by TTNS was time to first passage of flatus after right hemicolectomy (reduced from 46 to 33 h, p = 0.04). However, if only patients with low compliance to early oral nutrition (63 of 340; 18.5%) were considered, a statistically significant difference in time until first flatus (p < 0.01) and first bowel movement (p < 0.0001) and a shorter time until discharge (median 5 vs 7 days) were found in both left and right colectomies groups, respectively.

CONCLUSIONS

TTNS may have a positive effect on gastrointestinal tract motility and recovery from POI after colorectal surgery in a selected group, who has low compliance with an ERAS program, without increasing the risk of complications.

Combined Surgery and Extensive Intraoperative Peritoneal Lavage vs Surgery Alone for Treatment of Locally Advanced Gastric Cancer: The SEIPLUS Randomized Clinical Trial

Importance

Peritoneal metastasis is the most frequent pattern of postoperative recurrence in patients with gastric cancer. Extensive intraoperative peritoneal lavage (EIPL) is a new prophylactic strategy for treatment of peritoneal metastasis of locally advanced gastric cancer; however, the safety and efficacy of EIPL is currently unknown.

Objective

To evaluate short-term outcomes of patients with advanced gastric cancer who received combined surgery and EIPL or surgery alone.

Design, Setting, and Participants

From March 2016 to November 2017, 662 patients with advanced gastric cancer receiving D2 gastrectomy were enrolled in a large, multicenter, randomized clinical trial from 11 centers across China. In total, 329 patients were randomly assigned to receive surgery alone, and 333 patients were randomly assigned to receive surgery plus EIPL. Clinical characteristics, operative findings, and postoperative short-term outcomes were compared between the 2 groups in the intent-to-treat population.

Main Outcomes and Measures

Short-term postoperative complications and mortality.

Results

The present analysis included data from 550 patients, 390 men and 160 women, with a mean (SD) age of 60.8 (10.7) years in the surgery alone group and 60.6 (10.8) in the surgery plus EIPL group. Patients assigned to the surgery plus EIPL group exhibited reduced mortality (0 of 279 patients) compared with those assigned to surgery alone (5 of 271 patients [1.9%]) (difference, 1.9%; 95% CI, 0.3%-3.4%; P = .02). A significant difference in the overall postoperative complication rate was observed between patients receiving surgery alone (46 patients [17.0%]) and those receiving surgery plus EIPL (31 patients [11.1%]) (difference, 5.9%; 95% CI, 0.1%-11.6%; P = .04). Postoperative pain occurred more often following surgery alone (48 patients [17.7%]) than following surgery plus EIPL (30 patients [10.8%]) (difference, 7.0%; 95% CI, 0.8%-13.1%; P = .02).

Conclusions and Relevance

Inclusion of EIPL can increase the safety of D2 gastrectomy and decrease postoperative short-term complications and wound pain. As a new, safe, and simple procedure, EIPL therapy is easily performed anywhere and does not require any special devices or techniques. Our study suggests that patients with advanced gastric cancer appear to be candidates for the EIPL approach.

Trial Registration

ClinicalTrials.gov identifier: NCT02745509.

Mechanism of Electroacupuncture on Postoperative Ileus Induced by Surgical Stress in Rats

Objectives: Acupuncture has been used for treating gastrointestinal (GI) disorders such as postoperative nausea and vomiting. Electroacupuncture (EA) accelerates GI transit following surgery and ameliorates postoperative ileus (POI) to restore colonic transit (CT); however, the mechanisms of this EA-induced restoration remain unclear. The aims of this study were to show CT following surgery and the effects of EA at ST 36 on POI induced by surgical stress (SS) in 45 conscious, male Sprague-Dawley rats. Materials and Methods: An operation was performed in each rat, setting a cannula into the cecum to connect the proximal colon to inject markers. On the day after surgery, 20 metal radiopaque markers were administered to the proximal colon of each rat. These markers were visible throughout the GI tract on soft X-ray immediately after administration and up to 240 minutes afterward. The rats were divided into 5 groups with 9 rats in each group: (1) SS; (2) 5 days post surgery (POST-5D); (3) SS + phentolamine; (4) EA alone; and (5) EA + atropine. The EA was performed at ST 36 for 20 minutes at a frequency of 10 Hz and agents were administered in the appropriate groups before markers were administered and measurements were taken. Measurements were performed the day after surgery except in the POST 5-D group. CT was calculated by the geometric center on the images showing the CT for each rat. Results: CT after surgery was delayed significantly and phentolamine accelerated CT. EA restored CT following surgery and atropine abolished the effect of EA on CT. Conclusions: The current study demonstrated that surgery induced a delay in CT through the sympathetic pathway via α-adrenoreceptors; CT was restored by EA. These results suggest that EA can be used to treat POI through mediation of the autonomic nervous system.

Anti-inflammatory Effects of Enhanced Recovery Programs on Early-Stage Colorectal Cancer Surgery

BACKGROUND

Postoperative ileus (POI) is observed in 20-30% of patients undergoing colorectal cancer surgery, despite enhanced recovery programs (ERPs). Cyclooxygenase (COX)-2 is identified as a key enzyme in POI, but other arachidonic acid pathway enzymes have received little attention despite their potential as selective targets to prevent POI. The objectives were to compare the expression of arachidonic acid metabolism (AAM) enzymes (1) between patients who underwent colorectal cancer surgery and followed an ERP or not (NERP), (2) and between ERP patients who experimented POI or not and (3) to determine the ability of antagonists of these pathways to modulate contractile activity of colonic muscle.

METHODS

This was a translational study. Main outcome measures were gastrointestinal motility recovery data, mRNA expressions of key enzymes involved in AAM (RT-qPCR) and ex vivo motility values of the circular colon muscle. Twenty-eight prospectively included ERP patients were compared to eleven retrospectively included NERP patients that underwent colorectal cancer surgery.

RESULTS

ERP reduced colonic mucosal COX-2, microsomal prostaglandin E synthase (mPGES1) and hematopoietic prostaglandin D synthase (HPGDS) mRNA expression. mPGES1 and HPGDS mRNA expression were significantly associated with ERP compliance (respectively, r2 = 0.25, p = 0.002 and r2 = 0.6, p < 0.001). In muscularis propria, HPGDS mRNA expression was correlated with GI motility recovery (p = 0.002). The pharmacological inhibition of mPGES1 increased spontaneous ex vivo contractile activity in circular muscle (p = 0.03).

CONCLUSION

The effects of ERP on GI recovery are correlated with the compliance of ERP and could be mediated at least in part by mPGES1, HPGDS and COX-2. Furthermore, mPGES1 shows promise as a therapeutic target to further reduce POI duration among ERP patients.

Nonsteroidal anti-inflammatory drugs reduce the time to recovery of gut function after elective colorectal surgery: a systematic review and meta-analysis

AIM

Postoperative ileus causes significant patient morbidity after abdominal surgery. Some evidence suggests nonsteroidal anti-inflammatory drugs (NSAIDs) may reduce time to gut recovery, but there has not been a meta-analysis to assess their efficacy. This systematic review and meta-analysis aimed to determine the benefit of NSAIDs for recovery of postoperative gut function in patients undergoing elective colorectal surgery.

METHOD

MEDLINE, EMBASE, CENTRAL and reference lists were searched with no date or language restrictions. Randomized controlled trials comparing the use of NSAIDs with placebo in the perioperative or postoperative period were identified. Included studies reported outcomes relevant to gut function: time to pass flatus or stool and time to tolerate an oral diet. The mean difference in time from surgery until passage of flatus, stool and tolerance of diet were meta-analysed using a random-effects model in RevMan 5.3.

RESULTS

This study identified 992 relevant articles. Five randomized controlled trials on patients undergoing elective colorectal surgery met our inclusion criteria and were meta-analysed. Compared with placebo, NSAIDs significantly improved the time to pass flatus (mean difference -9.44 h, 95% CI: -17.22, -1.65, I² = 70%, P = 0.02), time to pass stool (mean difference -12.09 h, 95% CI: -17.16, -7.02, I² = 0%, P < 0.001) and time to tolerate a diet (mean difference -11.95 h, 95% CI: -18.66, -5.24, I² = 0%, P < 0.001).

CONCLUSION

NSAIDs significantly improve time to gut recovery after elective colorectal surgery. Current evidence is not adequate to identify whether selective or nonselective drugs should be recommended. Further high-power studies using selective drugs are required.

Role of transient receptor potential melastatin 2 in surgical inflammation and dysmotility in a mouse model of postoperative ileus

In this study, we investigated the role of transient receptor potential melastatin 2 (TRPM2), a nonselective cation channel abundantly expressed in inflammatory cells such as macrophages, in the development of postoperative ileus, a complication of abdominal surgery characterized by gastrointestinal dysmotility. In wild-type mice, we found that intestinal manipulation, a maneuver that elicits symptoms typical of postoperative ileus, delays the transit of fluorescein-labeled dextran, promotes the infiltration of CD68⁺ macrophages, Ly6B.2⁺ neutrophils, and MPO⁺ cells into intestinal muscles, boosts expression of IL-1β, IL-6, TNF-α, iNOS, and CXCL2 in intestinal muscles and peritoneal macrophages, enhances phosphorylation of ERK and p38 MAPK in intestinal muscles, and amplifies IL-1β, IL-6, TNF-α, iNOS, and CXCL2 expression in resident and thioglycolate-elicited peritoneal macrophages following exposure to lipopolysaccharide. Remarkably, TRPM2 deficiency completely blocks or diminishes these effects. Indeed, intestinal manipulation appears to activate TRPM2 in resident muscularis macrophages and elicits release of inflammatory cytokines and chemokines, which, in turn, promote infiltration of macrophages and neutrophils into the muscle, ultimately resulting in dysmotility. NEW & NOTEWORTHY Activation of transient receptor potential melastatin 2 (TRPM2) releases inflammatory cytokines and chemokines, which, in turn, promote the infiltration of inflammatory cells and macrophages into intestinal muscles, ultimately resulting in dysmotility. Thus TRPM2 is a promising target in treating dysmotility due to postoperative ileus, a complication of abdominal surgery.

Intestinal pseudo-obstruction caused by herpes zoster: Case report and pathophysiology

Herpes zoster (HZ) infection occurs in approximately 10% to 30% of individuals. Visceral neuropathies secondary to HZ can cause cystitis and urinary retention. But colonic pseudo-obstruction can also occur. Peripheral neuropathy may reveal segmental motor paresis of either upper or lower limbs, the abdominal muscles or the diaphragm. We report the case of a 62-year-old male patient who presented with abdominal distention and cutaneous vesicular eruption on the left side of the abdominal wall. Plain X-rays and computed tomography scan showed distended small bowel. A diagnosis of intestinal pseudo-obstruction was made secondary to segmental paresis of the small intestine and visceral neuropathy. Conservative management was successful and the patient was discharged uneventfully. Intestinal pseudo-obstruction ought to be considered when dealing with non-obstructive (adynamic) conditions of the digestive tract associated with HZ infection; since early recognition may help to avoid unnecessary surgery.

Alterations in the gut barrier and involvement of Toll-like receptor 4 in murine postoperative ileus

BACKGROUND

The changes in the gut barrier (GB) and associated mechanisms in postoperative ileus (POI) are still unclear. Toll-like receptor 4 (TLR4) is involved in inflammation, which may cause GB dysfunction and POI. Here, the roles of the GB in POI in relation to TLR4-dependent signaling pathways were explored.

METHODS

POI was induced by small bowel manipulation in wild-type (WT) and TLR4-knockout (TLR4-/-) mice. Twenty-four hours after manipulation, indices of gastrointestinal (GI) transit, GB structure and function, inflammation, and related signaling pathways were analyzed.

KEY RESULTS

Normal GI motility and GB function were not affected by TLR4 knockout. Compared with WT POI mice, TLR4-/-POI mice showed milder GI transit retardation, GB dysfunction, and inflammatory responses. In WT mice, GB disorder was characterized by colonic goblet cells depletion, increased gut claudin-2 expression, and decreased CD4+/CD8+ ratios in intestinal Peyer's patches. Green fluorescent protein-tagged Escherichia coli in the gut was detected in plasma and extraintestinal organs, followed with increased plasma lipopolysaccharide. These changes displayed in WT POI mice were less severe in TLR4-/-POI mice. Furthermore, the mRNA and protein expression of interleukin-6, monocyte chemotactic protein-1, pp38 and pJNK in the intestine, and TNF-α level in plasma were significantly increased in WT, but not TLR4-/-POI mice.

CONCLUSIONS & INFERENCES

These results indicate that GB is impaired in the experimental POI, with inflammation being involved in this pathological process. TLR4 deficiency alleviated GB dysfunction and suppressed inflammation by disrupting the activation of mitogen-activated protein kinase signaling pathways, thereby ameliorating POI.

Irf4-dependent CD103+CD11b+ dendritic cells and the intestinal microbiome regulate monocyte and macrophage activation and intestinal peristalsis in postoperative ileus

OBJECTIVE

Postoperative ileus (POI), the most frequent complication after intestinal surgery, depends on dendritic cells (DCs) and macrophages. Here, we have investigated the mechanism that activates these cells and the contribution of the intestinal microbiota for POI induction.

DESIGN

POI was induced by manipulating the intestine of mice, which selectively lack DCs, monocytes or macrophages. The disease severity in the small and large intestine was analysed by determining the distribution of orally applied fluorescein isothiocyanate-dextran and by measuring the excretion time of a retrogradely inserted glass ball. The impact of the microbiota on intestinal peristalsis was evaluated after oral antibiotic treatment.

RESULTS

We found that Cd11c-Cre⁺ Irf4^flox/flox mice lack CD103⁺CD11b⁺ DCs, a DC subset unique to the intestine whose function is poorly understood. Their absence in the intestinal muscularis reduced pathogenic inducible nitric oxide synthase (iNOS) production by monocytes and macrophages and ameliorated POI. Pathogenic iNOS was produced in the jejunum by resident Ly6C^- macrophages and infiltrating chemokine receptor 2-dependent Ly6C⁺ monocytes, but in the colon only by the latter demonstrating differential tolerance mechanisms along the intestinal tract. Consistently, depletion of both cell subsets reduced small intestinal POI, whereas the depletion of Ly6C⁺ monocytes alone was sufficient to prevent large intestinal POI. The differential role of monocytes and macrophages in small and large intestinal POI suggested a potential role of the intestinal microbiota. Indeed, antibiotic treatment reduced iNOS levels and ameliorated POI.

CONCLUSIONS

Our findings reveal that CD103⁺CD11b⁺ DCs and the intestinal microbiome are a prerequisite for the activation of intestinal monocytes and macrophages and for dysregulating intestinal motility in POI.

Postoperative Ileus: Pathophysiology, Current Therapeutic Approaches

Postoperative ileus, which develops after each abdominal surgical procedure, is an iatrogenic disorder characterized by a transient inhibition of gastrointestinal motility. Its pathophysiology is complex involving pharmacological (opioids, anesthetics), neural, and immune-mediated mechanisms. The early neural phase, triggered by activation of afferent nerves during the surgical procedure, is short lasting compared to the later inflammatory phase. The latter starts after 3-6 h and lasts several days, making it a more interesting target for treatment. Insight into the triggers and immune cells involved is of great importance for the development of new therapeutic strategies. In this chapter, the pathogenesis and the current therapeutic approaches to treat postoperative ileus are discussed.

Abdominal surgery induced gastric ileus and activation of M1-like macrophages in the gastric myenteric plexus: prevention by central vagal activation in rats

Inflammation plays a role in abdominal surgery (AS)-induced intestinal ileus that is alleviated by electrical vagal stimulation. Intracisternal injection of RX-77368, the stable thyrotropin-releasing hormone agonist, activates dorsal motor nucleus neurons and gastric vagal efferent discharges. We investigated the gastric inflammation induced by AS and the modulation by intracisternal RX-77368 in rats. RX-77368 (50 ng/rat) or saline was injected followed, 1 h later, by laparotomy and small intestinal/cecal manipulation. The sham group had anesthesia alone. After 6 h, gastric emptying (GE) and the inflammation in gastric corpus were determined. AS inhibited GE by 72% vs. control and doubled the number of M1-like macrophage immunoreactive for major histocompatibility complex class II (MHCII; M1 marker) but not for cluster of differentiation 206 (CD206; M2 marker) (MHCII⁺/CD206^-) while there was no change in M2-like macrophages (MHCII^-/CD206⁺). AS increased mRNA levels of interleukin-1β (IL-1β) and tumor necrosis factor α (TNF-α) by 1.7- and 1.5-fold, respectively, in the gastric submucosa plus muscle layers and the infiltration of neutrophils labeled by myeloperoxidase by 9.5-fold in the muscularis externa. RX-77368 inhibited AS-related gastric changes while not altering these parameters in the sham group. There was a significant negative correlation between GE and IL-1β (r = -0.46), TNF-α (r = -0.44), M1 macrophage (r = -0.82), and neutrophils (r = -0.91). The M2-like macrophages and IL-10 expression were unchanged by AS with intracisternal saline or RX-77368. These data indicate that AS activates gastric M1 macrophages and increases proinflammatory cytokines expression, which are prevented by central vagal activation and may contribute to the correlated dampening of postoperative gastric ileus.NEW & NOTEWORTHY MHCII⁺/CD206^- (M1) and MHCII^-/CD206⁺ (M2) constitute two distinct populations of macrophages that are in close apposition to the cholinergic neurons in the rat gastric myenteric plexus (MP). Abdominal surgery (6 h) activates M1 macrophage leading to inflammation in the gastric MP correlated with the delayed gastric emptying, which was abolished by central vagal stimulation via intracisternal injection of RX-77368. Vagal stimulation linked with the cephalic phase may have potential beneficial effects to curtail postoperative gastric ileus.

The 5-HT4 receptor agonist prucalopride does not facilitate cholinergic neurotransmission in circular and longitudinal smooth muscle preparations of equine mid-jejunum

BACKGROUND

Postoperative ileus (POI) remains an important cause of death in horses. The recently developed selective 5-HT₄ receptor agonists such as prucalopride target 5-HT₄ receptors on myenteric cholinergic neurons to enhance acetylcholine release and GI motility. No clearcut in vitro evaluation whether highly selective 5-HT₄ receptor agonists enhance submaximal cholinergic neurotransmission towards the muscle layer has been performed in horses.

OBJECTIVES

To identify functional 5-HT₄ receptors in equine jejunum.

STUDY DESIGN

In vitro experimental study.

METHODS

Circular and longitudinal smooth muscle strips (mid-jejunum) were mounted in organ baths between 2 platinum electrodes allowing electrical field stimulation (EFS). To delineate the conditions to obtain purely cholinergic responses, voltage-response curves were studied. To investigate the influence of prucalopride and 5-HT, submaximal cholinergic contractions at a single voltage were induced.

RESULTS

In circular and longitudinal strips, EFS induced voltage-dependent neurogenic on-contractions when the bathing medium contained a NO-synthesis inhibitor and apamin to prevent inhibitory responses to NO and ATP. Contractions at a voltage inducing 50% of maximal amplitude were cholinergic, as they were blocked by atropine. These contractions were not influenced by prucalopride (up to 3μM), even in the presence of the phosphodiesterase inhibitor isobutyl-methyl-xanthine to inhibit breakdown of the second messenger of 5-HT₄ receptors, cAMP. Also the full 5-HT₄ receptor agonist 5-HT did not influence the EFS-induced submaximal cholinergic contractions. Moreover, prucalopride did not influence muscle tone continuously enhanced with KCl.

CONCLUSIONS

There are no functional 5-HT₄ receptors on myenteric cholinergic neurons nor muscular 5-HT₄ receptors in equine jejunum.

Intestinal T lymphocyte homing is associated with gastric emptying and epithelial barrier function in critically ill: a prospective observational study

Background

Impaired gastric emptying is common in critically ill patients. Intestinal dysmotility, a major cause of feed intolerance, may foster infectious complications due to mucosal barrier disruption. However, little is known about gut-directed immune activation, intestinal barrier function and its association with impaired gastric emptying in critically ill patients at ICU admission.

Methods

We conducted a prospective observational study at two tertiary care medical ICUs. Fifty consecutive patients needing invasive mechanical ventilation were recruited within 24 h of ICU admission, prior to any nutritional support. The acute physiology and chronic health evaluation (APACHE) II score, the sequential organ failure assessment (SOFA) score and the multiple organ dysfunction score (MODS) were used to assess illness severity and multiple organ dysfunction. Gastric emptying was assessed by paracetamol absorption test. Peripheral blood mononuclear cells were freshly isolated and cultured for 24 h, and TNF-α, IL-1β and IL-10 measured in cell culture supernatants and in serum by ELISA. The intestinal epithelial barrier was assessed, quantifying serum concentrations of intestinal fatty acid binding protein (I-FABP), ileal bile-acid binding protein (I-BABP) and zonulin-1 by ELISA. Small bowel homing T lymphocytes (CD4+ α4β7 + CCR9+) were analyzed by flow cytometry. The Mann-Whitney test and Spearman correlation were used in statistical evaluation.

Results

CD4 + α4β7 + CCR9+ T lymphocytes were inversely correlated with gastric emptying. Patients with delayed gastric emptying at ICU admission (n = 35) had significantly higher serum and PBMC-induced TNF-α and IL-1β and increased intestinal barrier disruption reflected by higher I-FABP, I-BABP and zonulin-1. Patients who died in the ICU had significantly impaired gastric empting at admission compared to ICU survivors. No differences were observed in APACHE II, SOFA or MODS in patients with delayed gastric emptying compared to patients with normal gastric emptying.

Conclusions

Exaggerated CD4 + α4β7 + CCR9+ T lymphocyte homing with increased pro-inflammatory cytokine release and intestinal epithelial barrier disruption are associated with delayed gastric emptying. This is not simply due to differences in overall severity of illness at ICU admission and may represent a pathophysiological mechanism of gut-directed immune activation leading to impaired barrier function in the critically ill.

Establishing a biomarker for postoperative ileus in humans - Results of the BiPOI trial

AIMS

Postoperative ileus (POI) is a frequent complication after abdominal surgery, resulting from an inflammation of the muscularis externa (ME). So far no valid biomarker for occurrence, duration or intensity of POI exists. Extravasation of monocytes and neutrophils from blood circulating into the postoperative ME is well known as a hallmark of POI. In a previous study we demonstrated that a low abundant subset of TH1 cells, activated by IL-12, can be detected in the peripheral blood of a small subset of patients in response to abdominal surgery. The aim of the present study was to investigate if these specific TH1 cells, IL-12 or circulating leukocyte levels could act as a valid marker for POI occurrence.

MAIN METHODS

At different time points, blood samples of patients undergoing abdominal or extraabdominal surgery were collected. Serum levels of IL-12 or TH1 cells as well as neutrophils and monocytes were analyzed. Data were compared between both groups and correlated with clinical signs of POI.

KEY FINDINGS

Time until first flatus and defecation as well as solid food tolerances are delayed after abdominal compared to extraabdominal surgery. Circulating IL-12 levels and numbers of TH1 cells, neutrophils and monocytes did not differ between both groups.

SIGNIFICANCE

While previous experiments indicated that specific TH1 cells play a crucial role in POI dissemination, our present data from a larger human cohort demonstrate that they do not seem to be suitable to distinguish between abdominal and extraabdominal surgery. Furthermore neither TH1 cells nor leukocytes or serum IL-12 levels are appropriate biomarkers for POI in a clinical setting.

Transforming growth factor-beta 3 alters intestinal smooth muscle function: implications for gastroschisis-related intestinal dysfunction

BACKGROUND

Gastroschisis (GS) is a congenital abdominal wall defect that results in the development of GS-related intestinal dysfunction (GRID). Transforming growth factor-β, a pro-inflammatory cytokine, has been shown to cause organ dysfunction through alterations in vascular and airway smooth muscle. The purpose of this study was to evaluate the effects of TGF-β3 on intestinal smooth muscle function and contractile gene expression.

METHODS

Archived human intestinal tissue was analyzed using immunohistochemistry and RT-PCR for TGF-β isoforms and markers of smooth muscle gene and micro-RNA contractile phenotype. Intestinal motility was measured in neonatal rats ± TGF-β3 (0.2 and 1 mg/kg). Human intestinal smooth muscle cells (hiSMCs) were incubated with fetal bovine serum ± 100 ng/ml of TGF-β 3 isoforms for 6, 24 and 72 h. The effects of TGF-β3 on motility, hiSMC contractility and hiSMC contractile phenotype gene and micro-RNA expression were measured using transit, collagen gel contraction assay and RT-PCR analysis. Data are expressed as mean ± SEM, ANOVA (n = 6-7/group).

RESULTS

GS infants had increased immunostaining of TGF-β3 and elevated levels of micro-RNA 143 & 145 in the intestinal smooth muscle. Rats had significantly decreased intestinal transit when exposed to TGF-β3 in a dose-dependent manner compared with Sham animals. TGF-β3 significantly increased hiSMC gel contraction and contractile protein gene and micro-RNA expression.

CONCLUSION

TGF-β3 contributed to intestinal dysfunction at the organ level, increased contraction at the cellular level and elevated contractile gene expression at the molecular level. A hyper-contractile response may play a role in the persistent intestinal dysfunction seen in GRID.

Pain management in patients with inflammatory bowel disease: translational approaches from bench to bedside

Abdominal pain is a common symptom in patients with inflammatory bowel disease (IBD) that negatively affects quality of life and can lead to increased health-seeking behavior. Although abdominal pain has been traditionally attributed to inflammation, there is growing literature demonstrating the existence of functional abdominal pain in patients with IBD, of which there are a variety of potential causes. Thus, when approaching a patient with IBD who has abdominal pain, in addition to IBD-related complications (e.g., inflammation/stricture), it is important to screen for related contributors, including peripheral factors (visceral hypersensitivity, bacterial overgrowth, and bowel dysmotility) and centrally mediated neurobiological and psychosocial underpinnings. These central factors include psychological symptoms/diagnoses, sleep disturbance, and stress. Opioid-induced hyperalgesia (e.g., narcotic bowel syndrome) is also growing in recognition as a potential central source of abdominal pain. This review draws from clinical studies and animal models of colitis and abdominal pain to consider how knowledge of these potential etiologies can be used to individualize treatment of abdominal pain in patients with IBD, including consideration of potential novel treatment modalities for the future. Accurate assessment of the source(s) of pain in patients with IBD can help guide appropriate diagnostic workup and use of disease-modifying therapy.

Blockade of p38 mitogen-activated protein kinase pathway ameliorates delayed gastric emptying in streptozotocin-induced diabetic rats

BACKGROUND AND AIM

Gastrointestinal dysfunction is one of the major complications of diabetes. The roles of inflammation in diabetes and its associated complications are increasingly recognized. p38 mitogen-activated protein kinase (MAPK) has been shown to be involved in the production of pro-inflammatory mediators. The aims of this study were to investigate the effects of SB203580, a specific p38 MAPK inhibitor, on delayed gastric emptying in diabetic rats and to elucidate its possible mechanism.

METHODS

SB203580 was administered in diabetic rats induced by intraperitoneal injection of streptozotocin. The gastric emptying rate of rats was measured by using phenol red solution, and blood glucose levels and body weights were observed. p38 MAPK activity and iNOS expression were assessed by Western blot analysis. The expression of tumor necrosis factor (TNF)-α and interleukin (IL)-1β were determined by enzyme-linked immunosorbent assay.

RESULTS

Gastric emptying was delayed significantly in diabetic rats and improved significantly with SB203580; high glucose significantly activated p38 MAPK and increased the expression of iNOS, TNF-α and IL-1β. The administration of SB203580 led to a significant decrease in the activation of p38 MAPK and the expression of iNOS, TNF-α and IL-1β.

CONCLUSIONS

Inflammation was associated with the development of delayed gastric emptying, and blockade of p38 MAPK pathway with SB203580 ameliorates delayed gastric emptying in diabetic rats, at least in part, by inhibiting the expression of iNOS, TNF-a and IL-1β. Therefore, p38MAPK may serve as a novel target for the therapy of diabetes-related gastrointestinal dysmotility.

Electrocautery-induced localized colonic injury elicits increased levels of pro-inflammatory cytokines in small bowel and decreases jejunal alanine absorption

BACKGROUND

Colitis is associated with functional abnormalities in proximal non-inflamed gut areas, but animal models to study small bowel dysfunction in colitis have limitations. This study aims to determine small intestinal alanine absorption and cytokine expression in a novel model of colonic ulceration induced by electro-cautery.

METHODS

A descending colon ulcer was induced in rats by a bipolar electro-cautery probe. Ulcer score was determined using Satoh's criteria. Jejunal alanine absorption was measured immediately and at different time intervals post ulcer induction. Levels of interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) protein and m-RNA were determined in mucosal scrapings obtained from the colon, duodenum, jejunum and ileum at various time intervals after colonic ulcer induction.

RESULTS

The mean ulcer score was 3 up to 48h, followed by healing by 96h post ulcer induction. Small bowel histology was normal throughout. Jejunal alanine absorption was reduced by 12-34% immediately and up to 72h after cautery and returned to normal at 96h. IL-1 and TNF-α mRNA increased significantly in the colon, duodenum, jejunum and ileum 3h post electro-cautery and returned to normal at 48h, while that of IL-6 increased significantly at 48h post ulcer induction. Similarly, IL-1, IL-6 and TNF-α protein levels increased in the duodenum, jejunum, ileum and colon up to 48h post ulcer induction.

CONCLUSIONS

Electrically induced localized colonic injury increased production of pro-inflammatory cytokines in non-inflamed segments of the small intestine and was associated with derangements of jejunal absorptive function.

Effects of experimental mechanical manipulations on local inflammation in the jejunum of horses

OBJECTIVE

To determine characteristics of the inflammatory reaction in the jejunum of horses in response to various mechanical manipulations.

ANIMALS

12 adult warm blood horses without gastrointestinal tract disorders.

PROCEDURES

The proximal aspect of the jejunum in each horse was divided into 5 segments, and the following manipulations were performed: manual emptying, placement of Doyen forceps, enterotomy alone, enterotomy with mucosal abrasion, and serosal abrasion. Jejunum samples were collected before (control), immediately after, and 30 minutes after the end of manipulations and histologically evaluated to determine distribution of neutrophils and eosinophils.

RESULTS

Macroscopically, all manipulations resulted in jejunal hemorrhage and edema. Compared with control samples, neutrophil numbers were significantly higher after manipulations in the serosa (after all manipulation types), circular muscle layer (after manual emptying), submucosa (after placement of Doyen forceps), and mucosa (after all manipulations except enterotomy alone). Eosinophil numbers were significantly higher in the submucosa after mechanical abrasion of the serosa and manual emptying versus control samples.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated mechanical manipulation of the jejunum resulted in local inflammatory reactions characterized predominantly by infiltration of neutrophils. This could contribute to the development of postoperative ileus or adhesions in horses without macroscopically detectable injury of the jejunum during surgery.

The spleen responds to intestinal manipulation but does not participate in the inflammatory response in a mouse model of postoperative ileus

Background

Postoperative ileus is characterized by a transient impairment of the gastrointestinal motility after abdominal surgery. The intestinal inflammation, triggered by handling of the intestine, is the main factor responsible for the prolonged dysmotility of the gastrointestinal tract. Secondary lymphoid organs of the intestine were identified as essential components in the dissemination of inflammation to the entire gastrointestinal tract also called field effect. The involvement of the spleen, however, remains unclear.

Aim

In this study, we investigated whether the spleen responds to manipulation of the intestine and participates in the intestinal inflammation underlying postoperative ileus.

Methods

Mice underwent Laparotomy (L) or Laparotomy followed by Intestinal Manipulation (IM). Twenty-four hours later, intestinal and colonic inflammation was assessed by QPCR and measurement of the intestinal transit was performed. Analysis of homeostatic chemokines in the spleen was performed by QPCR and splenic cell populations analysed by Flow Cytometry. Blockade of the egress of cells from the spleen was performed by administration of the Sphingosine-1-phosphate receptor 1 (S1P₁) agonist CYM-5442 10 h after L/IM.

Results

A significant decrease in splenic weight and cellularity was observed in IM mice 24 h post-surgery, a phenomenon associated with a decreased splenic expression level of the homeostatic chemokine CCL19. Splenic denervation restored the expression of CCL19 and partially prevented the reduction of splenocytes in IM mice. Treatment with CYM-5442 prevented the egress of splenocytes but did not ameliorate the intestinal inflammation underlying postoperative ileus.

Conclusions

Intestinal manipulation results in two distinct phenomena: local intestinal inflammation and a decrease in splenic cellularity. The splenic response relies on an alteration of cell trafficking in the spleen and is partially regulated by the splenic nerve. The spleen however does not participate in the intestinal inflammation during POI.

A distinct vagal anti-inflammatory pathway modulates intestinal muscularis resident macrophages independent of the spleen

The cholinergic anti-inflammatory pathway (CAIP) has been proposed as a key mechanism by which the brain, through the vagus nerve, modulates the immune system in the spleen. Vagus nerve stimulation (VNS) reduces intestinal inflammation and improves postoperative ileus. We investigated the neural pathway involved and the cells mediating the anti-inflammatory effect of VNS in the gut. The effect of VNS on intestinal inflammation and transit was investigated in wild-type, splenic denervated and Rag-1 knockout mice. To define the possible role of α7 nicotinic acetylcholine receptor (α7nAChR), we used knockout and bone marrow chimaera mice. Anterograde tracing of vagal efferents, cell sorting and Ca(2+) imaging were used to reveal the intestinal cells targeted by the vagus nerve. VNS attenuates surgery-induced intestinal inflammation and improves postoperative intestinal transit in wild-type, splenic denervated and T-cell-deficient mice. In contrast, VNS is ineffective in α7nAChR knockout mice and α7nAChR-deficient bone marrow chimaera mice. Anterograde labelling fails to detect vagal efferents contacting resident macrophages, but shows close contacts between cholinergic myenteric neurons and resident macrophages expressing α7nAChR. Finally, α7nAChR activation modulates ATP-induced Ca(2+) response in small intestine resident macrophages. We show that the anti-inflammatory effect of the VNS in the intestine is independent of the spleen and T cells. Instead, the vagus nerve interacts with cholinergic myenteric neurons in close contact with the muscularis macrophages. Our data suggest that intestinal muscularis resident macrophages expressing α7nAChR are most likely the ultimate target of the gastrointestinal CAIP.

Involvement of interleukin-17A-induced hypercontractility of intestinal smooth muscle cells in persistent gut motor dysfunction

BACKGROUND AND AIM

The etiology of post-inflammatory gastrointestinal (GI) motility dysfunction, after resolution of acute symptoms of inflammatory bowel diseases (IBD) and intestinal infection, is largely unknown, however, a possible involvement of T cells is suggested.

METHODS

Using the mouse model of T cell activation-induced enteritis, we investigated whether enhancement of smooth muscle cell (SMC) contraction by interleukin (IL)-17A is involved in postinflammatory GI hypermotility.

RESULTS

Activation of CD3 induces temporal enteritis with GI hypomotility in the midst of, and hypermotility after resolution of, intestinal inflammation. Prolonged upregulation of IL-17A was prominent and IL-17A injection directly enhanced GI transit and contractility of intestinal strips. Postinflammatory hypermotility was not observed in IL-17A-deficient mice. Incubation of a muscle strip and SMCs with IL-17A in vitro resulted in enhanced contractility with increased phosphorylation of Ser19 in myosin light chain 2 (p-MLC), a surrogate marker as well as a critical mechanistic factor of SMC contractility. Using primary cultured murine and human intestinal SMCs, IκBζ- and p38 mitogen-activated protein kinase (p38MAPK)-mediated downregulation of the regulator of G protein signaling 4 (RGS4), which suppresses muscarinic signaling of contraction by promoting inactivation/desensitization of Gαq/11 protein, has been suggested to be involved in IL-17A-induced hypercontractility. The opposite effect of L-1β was mediated by IκBζ and c-jun N-terminal kinase (JNK) activation.

CONCLUSIONS

We propose and discuss the possible involvement of IL-17A and its downstream signaling cascade in SMCs in diarrheal hypermotility in various GI disorders.

Prevention of duodenal ileus reveals functional differences in the duodenal response to luminal hypertonicity in Sprague-Dawley and Dark Agouti rats

AIM

The mechanism by which the duodenum adjusts the luminal osmolality remains unclear. The aim was to compare the duodenal osmoregulation in response to different hyperosmolar solutions in Sprague-Dawley and Dark Agouti rats and to elucidate whether cyclooxygenase-2 inhibition affects these responses.

METHODS

The duodenum was perfused in situ with a 700-milliosmolar solution (NaCl alone, D-glucose ± NaCl, D-mannitol ± NaCl or orange juice), and the effects on the duodenal motility, mucosal permeability, luminal alkalinization, fluid flux and osmoregulation were assessed in anaesthetized rats.

RESULTS

The change in net fluid flux and luminal osmolality, in response to a given hyperosmolar solution, was almost identical in control rats of both strains. In control rats, hypertonic D-glucose-NaCl induced fluid secretion only in the presence of phlorizin, an inhibitor of SGLT1. Cyclooxygenase-2 inhibition potentiated the hypertonicity-induced fluid secretion and increased the osmolality-adjusting capability in both strains, but the responses were greater in Dark Agouti rats. While cyclooxygenase-2-inhibited Dark Agouti rats responded to the hyperosmolar solutions with depression of motility and increased mucosal permeability, these effects were absent or smaller in the Sprague-Dawley strain. In contrast, orange juice induced the same duodenal responses in cyclooxygenase-2-inhibited Dark Agouti and Sprague-Dawley rats.

CONCLUSION

The duodenum possesses the ability to absorb fluid despite a very high luminal osmolality. Inhibition of cyclooxygenase-2 markedly enhanced the capability of the duodenum to secrete fluid and to decrease luminal osmolality, irrespective of the hyperosmolar solution or the rat strain used, and revealed notable differences between the two strains with regard to their osmolality-adjusting capability.

Glial-derived neurotrophic factor reduces inflammation and improves delayed colonic transit in rat models of dextran sulfate sodium-induced colitis

BACKGROUND

Intestinal inflammation is well known to cause gut dysmotility through the effects on the enteric nervous system. Glial-derived neurotrophic factor (GDNF) has been demonstrated to have anti-inflammatory effects and neuronal protective actions. The aim of this study was to investigate whether the GDNF could improve inflammation-induced gut dysmotility.

METHODS

Recombinant adenoviral vectors encoding GDNF (Ad-GDNF) were administered intracolonically in experimental colitis induced by dextran sulfate sodium (DSS). The disease activity index (DAI) and histological score were measured. Colonic transit was measured by using phenol red and assessed with the geometric center. PGP 9.5 immunostaining was used to examine the number and distribution of enteric neurons. The expression of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and myeloperoxidase (MPO) activity were measured by ELISA assay. The expression of Akt, caspase-3, bcl-2 and PGP 9.5 was analyzed by western blot assay.

RESULTS

A significant neuronal cell loss and a significant delay in colonic transit accompanied with the neuronal loss following inflammation were observed. GDNF prevented partially the loss of enteric neurons and ameliorated significantly experimental colitis and delayed colonic transit by, at least in part, down-regulation of TNF-α and IL-1β expression, decrease of infiltration of leukocytes, and inhibition of neuronal cell apoptosis.

CONCLUSIONS

GDNF reduces inflammation and improves delayed colonic transit in DSS-induced colitis. GDNF may be a useful therapeutic agent for the treatment of gut dysmotility in patients with UC.

Inflammatory responses in the muscle coat of stomach and small bowel in the postoperative ileus model of guinea pig

PURPOSE

Small intestinal function returns first after surgery, and then the function of the stomach returns to normal after postoperative ileus (POI). The aim of this study was to investigate inflammatory responses in the muscle coat of stomach and small intestine in guinea pig POI model.

MATERIALS AND METHODS

The distance of charcoal migration from pylorus to the distal intestine was measured. Hematoxylin and eosin (H&E) and immunohistochemical stain for calprotectin were done from the histologic sections of stomach, jejunum and ileum obtained at 3 and 6 hour after operation. Data were compared between sham operation and POI groups.

RESULTS

The distance of charcoal migration was significantly reduced in the 3 and 6 hour POI groups compared with sham operated groups (p<0.05). On H&E staining, the degree of inflammation was significantly higher in the stomach of 3 hour POI groups compared with jejunum and ileum of POI groups or sham operated groups (p<0.05). Calprotectin positive cells were significantly increased in the muscle coat of stomach of 3 hour POI groups compared with jejunum and ileum of POI groups or sham operated groups (p<0.05). There was strong association between the degree of inflammation and calprotectin positive cells in stomach.

CONCLUSION

Postoperative ileus induced by cecal manipulation significantly increased the degree of inflammation and calprotectin positive cells in the muscle coat of stomach as a remote organ. The relevance of degree of inflammation and the recovery time of ileus should be pursued in the future research.

Systemic inflammation with enhanced brain activation contributes to more severe delay in postoperative ileus

BACKGROUND

The severity of postoperative ileus (POI) has been reported to result from decreased contractility of the muscularis inversely related to the number of infiltrating leukocytes. However, we previously observed that the severity of POI is independent of the number of infiltrating leukocytes, indicating that different mechanisms must be involved. Here, we hypothesize that the degree of tissue damage in response to intestinal handling determines the upregulation of local cytokine production and correlates with the severity of POI.

METHODS

Intestinal transit, the inflammatory response, I-FABP (marker for tissue damage) levels and brain activation were determined after different intensities of intestinal handling.

KEY RESULTS

Intense handling induced a more pronounced ileus compared with gentle intestinal manipulation (IM). No difference in leukocytic infiltrates in the handled and non-handled parts of the gut was observed between the two intensities of intestinal handling. However, intense handling resulted in significantly more tissue damage and was accompanied by a systemic inflammation with increased plasma levels of pro-inflammatory cytokines. In addition, intense but not gentle handling triggered enhanced c-Fos expression in the nucleus of the solitary tract (NTS) and area postrema (AP). In patients, plasma levels of I-FABP and inflammatory cytokines were significantly higher after open compared with laparoscopic surgery, and were associated with more severe POI.

CONCLUSIONS & INFERENCES

Not the influx of leukocytes, rather the manipulation-induced damage and subsequent inflammatory response determine the severity of POI. The release of tissue damage mediators and pro-inflammatory cytokines into the systemic circulation most likely contribute to the impaired motility of non-manipulated intestine.

The role of lymphoid tissue in the attenuation of the postoperative ileus

Standardized intestinal manipulation (IM) leads to local bowel wall inflammation subsequently spreading over the entire gastrointestinal tract. Previously, we demonstrated that this so-called gastrointestinal field effect (FE) is immune-mediated. The aim of this study was to investigate the role of secondary lymphoid organs [mesenteric lymph nodes (MLN), gut-associated lymphoid tissue (GALT)] in IM-mediated FE by employing mice with deficient secondary lymphoid organs (aly/aly, MLN ex) or by administration of 2-amino-2-[2-(4-octylphenyl)ethyl]-1,3-propanediol (FTY720), an immunomodulating agent that inhibits emigration of lymphocytes out of lymphoid organs. Small bowel muscularis, and colonic muscularis from wild-type mice as control, from aly/aly mice, FTY720-treated mice (daily dose of 1.0 mg/kg mouse ip starting 3 days before surgical procedure), and wild-type mice that had undergone removal of mesenteric lymph nodes before IM (MLN ex mice) were obtained after selective IM of the jejunum or sham operation. FE was analyzed by measuring transit time of orally administered fluorescent dextran in the gastrointestinal tract [geometric center (GC) of fluorescent dextran], colonic transit time, infiltration of myeloperoxidase-positive cells, and circular smooth muscle contractility. Furthermore, mRNA levels of inflammatory cytokines [interleukin (IL)-6, tumor necrosis factor (TNF)-α, macrophage inflammatory protein (MIP)-1α] were determined by Taqman-PCR. We observed a significantly reduced upregulation of proinflammatory cytokines (IL-6, TNF-α, MIP-1α) in colonic muscularis of MLN ex mice, aly/aly mice, and FTY720-treated mice compared with wild-type mice. Contractility of circular muscularis strips of the colon but not the jejunum was significantly improved in aly/aly mice and FTY720-treated wild-type mice. Additionally, inflammation of the colon determined by the number of myeloperoxidase-positive cells and colonic transit time were significantly improved in aly/aly mice, FTY720-treated wild-type mice, and in MLN ex mice. In summary, lack of secondary lymphoid organs (MLN + GALT) in aly/aly mice or administration of FTY720 abrogated FE after IM as opposed to wild-type mice. These data demonstrate that secondary lymphoid organs are involved in the propagation of FE and postoperative ileus. FTY720 indirectly affects FE by inhibiting migration of activated T cells from the jejunum and adjacent secondary lymphoid organs to the colon. These findings support the crucial role of the adaptive immune system in FE, most likely by a sphyngosine 1-phosphate-dependent mechanism.

Mind-body medicine for multiple sclerosis: a systematic review

Background. Mind-body therapies are used to manage physical and psychological symptoms in many chronic health conditions. Objective. To assess the published evidence for using mind-body techniques for symptom management of multiple sclerosis. Methods. MEDLINE, PsycINFO, and Cochrane Clinical Trials Register were searched from inception to March 24, 2012. Eleven mind-body studies were reviewed (meditation, yoga, biofeedback, hypnosis, relaxation, and imagery). Results. Four high quality trials (yoga, mindfulness, relaxation, and biofeedback) were found helpful for a variety of MS symptoms. Conclusions. The evidence for mind-body medicine in MS is limited, yet mind-body therapies are relatively safe and may provide a nonpharmacological benefit for MS symptoms.